Polystyrene Formwork: Multifunctionality and Reliability

Polystyrene Formwork: Multifunctionality and Reliability

The classic version of the mold for the foundation and walls in monolithic houses is a temporary structure, which is made of wood and chipboard. Fixed polystyrene formwork made of expanded is an alternative construction method that does not require waste. This design increases the strength of the building and increases its energy efficiency, acting as thermal insulation. However, such material has some features that cannot be ignored.

Advantages of fixed polystyrene formwork

The manufacturers of this material indicate many of its advantages compared to standard versions of building formwork. These advantages must be known to every person who decides to use a fixed type of polystyrene foam construction.

The advantage of non-removable formwork made of this material is primarily that this design has auxiliary functions. The main one is the organization of the form for the walls and the foundation of the monolithic building. Due to its physical qualities, polystyrene foam is a good insulation. This is a very important property since this type of formwork cannot be dismantled after concrete has solidified.

If formwork boards are used, they must be dismantled. Wood is not a heat insulator, so polystyrene blocks are considered a more profitable investment. Fixed formwork of this material allows you to build a lightweight concrete structure. Moreover, such a building saves 30-35% more heat than a building with an analogue of red brick. Thus, the use of expanded polystyrene can reduce the cost of other materials from which the foundation or walls are made.

An alternative to polystyrene foam forms is plastic formwork. The price of this design is slightly higher, but it is more reliable. Fixed plastic elements can be purchased at a hardware store or place their order online.

polystyrene foam is a good insulation
Due to its physical qualities, polystyrene foam is a good insulation

Another advantage of such forms is that they protect the reinforced concrete from moisture. In winter, this is especially important. As a result, thanks to polystyrene foam blocks, the operational life of the foundation and walls is increased by approximately 20%. Quite often, it is this fact that encourages people to use such formwork for building a house. From polystyrene foam, various (in shape and dimensions) elements are made.

Note! Building a building using polystyrene forms reduces financial costs by about a third.

The price of formwork floors made of polystyrene foam, as a rule, is a determining factor in its selection. However, the most useful property of such forms is that their use allows preserving the structure of concrete at low temperatures (but not lower than +5 ° C). Concrete in this case hardens in the normal mode, which positively affects its qualities after solidification.

In turn, pouring concrete material into a wooden mold gives a completely different result. In such formwork (at low temperatures), concrete hardens faster, and its structure is broken.

Styrofoam formwork must not be used at temperatures below 5 ° C

Polystyrene formwork : design flaws

Similar designs have their drawbacks. Some of them are quite substantial. For example, one of the most serious drawbacks is the fact that a building made using such formwork cannot be rebuilt. Therefore, its design is recommended to be thought out in advance. In addition, all communications located in the structure should be laid at the construction stage.

A house of fixed formwork is carried out taking into account some rules, which are very important to observe in order to get a reliable building that is resistant to adverse environmental factors. Blocks made of polystyrene foam require careful installation. It is very important to maintain tightness, as otherwise moisture will penetrate into the voids.

Another drawback of this technology for the construction of residential buildings is that polystyrene molds cannot be used at temperatures below 5 ° C. In this situation, the concrete will simply not harden. In hot weather, concrete requires additional moisture, as otherwise it will solidify incorrectly.

formwork blocks
An important disadvantage of foam blocks is their fragility, so you need to work with them very carefully

It is also worth noting that fixed formwork blocks made of polystyrene foam interfere with normal ventilation of the concrete structure. The solution to the problem in this case is the installation of ventilation communications.This forced system will provide the necessary ventilation, while maintaining a high efficiency of a fixed structure.

Types of fixed formwork depending on the material of manufacture

Before starting installation, it is necessary to study various options for fixed formwork, which can be purchased today in the construction market. The main feature by which these products are classified is the material of manufacture. The choice of raw materials depends on the complexity of the future building and its individual characteristics. Consider the raw materials from which molds for concrete are most often made.

Styrofoam. Many people are interested in the question of what polystyrene foam is. This material is the standard raw material used in the manufacture of fixed formwork. The second name for expanded polystyrene is gas-filled polystyrene. It is characterized by a number of positive qualities that determine the popularity of using forms made from it.

Useful information! Expanded polystyrene is characterized by rather high strength characteristics and provides reliable thermal insulation of concrete.

polystyrene blocks
Expanded polystyrene formwork blocks are very light, so construction can be carried out without the use of heavy equipment

Arbolite. This material includes 2 main components: wood shavings and concrete. The individual elements of the permanent formwork made of wood concrete are represented by blocks. They have empty spaces, which during installation are reinforced and filled with mortar. The advantage of this raw material is that it has high strength.The soundproof qualities of wood concrete are also its strength. Of the minuses of this material used for the manufacture of formwork, low heat insulation and high cost can be noted.

Fiberboard. This raw material, like the previous one, consists of 2 components. The first of these is wood chips, which provides the fibrous structure of the individual elements of such formwork. The second component is an inorganic binder. The main advantage of this formwork is resistance to temperature fluctuations.

Chip cement. Such material is considered less popular than the above options for fixed formwork. The technology of installation of chip cement has its own nuances. Of the advantages of this material, it is worth highlighting a very good sound insulation and resistance to temperature fluctuations.

Arbolit includes two main components: wood shavings and concrete

Economical option: fixed penoplex formwork

Today there is the possibility of mounting a fixed formwork made of foam boards. This option is quite common, as it allows you to significantly save finances when building a house. Penoplex is a material used for insulation and has good strength characteristics. This allows it to be used as concrete forms.

Plates of foam plastic have dimensions of 60×100 cm. The dimensions of these products prevail over the parameters of standard structures made of polystyrene foam. In order to install the formwork around the house from foam, it is necessary to perform the correct calculation of the material. It is also important to understand that such products do not have their own locking elements. Thus, before purchasing the material, it is necessary to consider the system of fastenings of the individual parts to each other.

The use of foam allows to reduce financial costs to a minimum. This is especially felt when compared with the costs required for the construction of a standard design. The formwork of ceilings on telescopic racks, shields for walls and the use of plywood will cost much more.

Useful information! A common option for the organization of retainer parts is the use of special jumpers that are equipped with threads on the edges. Such elements are made of reinforcement. The main thing to remember is the installation of such jumpers between the foam sheets.

A similar embodiment of the design is less expensive, but at the same time more complicated due to the selection of latches. The price of fixed polystyrene formwork is higher, but its installation does not require unnecessary actions. If necessary, it is possible to purchase fixers for boards made of foam plastic, which are used in the installation of polystyrene foam construction.

Fixed penoplex formwork : varieties of structural parts

Formwork elements can have a different design, which is determined by their operational purpose. Today, there are such options for these products made of polystyrene foam:

  • panels;
  • blocks (cast and prefabricated);
  • wireframe systems.
Fixed foam formwork
There are several options for products made from polystyrene foam: panels, blocks and frame systems

Systems related to frame systems are double-circuit structures, between the walls of which there is an empty space. When mounted inside such a formwork, reinforcement is laid and the solution is poured. If you cut a finished wall made using this technology, you can distinguish three layers: two outer, represented by formwork, and the middle one made of reinforced concrete.

Foam blocks are divided into two large groups: cast and precast. During the assembly of the formwork, these elements are aligned in such a way that they are located on top of each other. Moreover, no bonding mixtures (for example, glue) are used for docking. Block layout is staggered.

Cast products are also called fuser. This is due to the fact that they have a fairly high density (up to 40 kg / m³). Structural features affect the thermal insulation characteristics. A block of this type consists of 2 sheets that are joined together by means of special jumpers. The assembly of such parts and the connection of their individual elements are carried out at the manufacturing stageIt is worth noting that such designs have one drawback: they warm up rather weakly. This is due to the location of the insulation on the inside of the wall pie.

When mounted
When mounted inside the formwork, reinforcement is laid and the solution is poured

The sizes of blocks of molded foam formwork can be different. However, products with dimensions of 1000x250x250 mm are considered the standard option. The mass of such a block is usually about 1 kg. The thickness of the insulation located on both sides (outside) is 50 mm. Accordingly, the same indicator of the concrete layer will be 150 mm.

Insulation in the forms that are used for pouring concrete can be different. The future design characteristics depend on the choice of insulator material. It is important to remember that such a layer traditionally performs two main functions. The first of them is forming, and the second is heat-insulatingThe cost of expanded polystyrene also varies depending on the type of blocks. How much do different types of shapes cost? Pricing takes into account the design, as well as the thickness of the insulation layer.

When mounted
Penoplex blocks are divided into two large groups: cast and precast

Note! Concreting in more than 3 rows is not recommended. An ideal option would be laying concrete in 2.5 rows, since in this case the seam will be located in the middle of the block.

Prefabricated polystyrene blocks for formwork

Formwork can be represented by prefabricated elements, which differ from cast ones in their structure and have some application features. These blocks consist of two sheets, which are assembled into a single structure before the start of installation work. It is important to note that such elements can be made not only from expanded polystyrene, but also from other materials. The distance between 1 and 2 sheets remains unchanged due to special components that are called spacers.

The construction of a house from a fixed formwork of this type has several features that need attention. The main difference between prefabricated forms is that their use allows you to use more than 3 layers in the walls. Moreover, the combination of materials in this case does not play a role, while structures made using cast blocks require strict adherence to the sequence of materials. The insulation in such a situation will always be located outside.

prefabricated elements
Formwork can be represented by prefabricated elements that differ from cast in its structure

A common solution is a wall cake, which includes two facing layers of hard sheet materialInsulating material (expanded polystyrene) is laid close to the outer sheet of this type. The second layer in this situation is reinforced concrete.

The project of a house of fixed formwork is made in advance. It indicates all the necessary data testifying to the design features, dimensions and individual solutions in accordance with the situation.

It is worth noting that such forms have one significant advantage over cast counterparts. It consists in the fact that, if necessary, it is possible to change the width of the internal cavity into which the fittings fit and the solution is poured. Changing this indicator is done through the use of spacers. If such a need arises, longer locking elements can be purchased.

All costs must be indicated in the estimate of the formwork. The device, prices, dimensions of individual elements – all this is recommended to be noted in the preliminary wiring diagram.

project of a house

Design features of prefabricated forms affect the degree of heating of the wall. The absence of foam allows you to increase this indicator. If necessary, collapsible structures used for the construction of buildings, you can do it yourself.

Installation of formwork for a strip foundation : installation features

The most popular type of foundation used in the independent construction of houses and other structures is tape. Before starting the organization of such a foundation, it is necessary to carry out appropriate preparatory work. These include project development and site preparation. In addition, you need to mark the place reserved for the construction of the base.

The formwork device for the strip foundation is not particularly difficult, however, there are some nuances that you need to know and observe. For example, it is recommended to fill in layers. The process itself is as follows: the cavity located in the block is filled with a solution of concrete, after which it remains only to wait for it to solidify.

Useful information! The organization of fittings is not a prerequisite. It fits if there is a need to increase the strength characteristics of the structure.

Reinforcement strapping is performed inside block elements. It is not necessary to dismantle polystyrene foam, since it will serve as a heat insulator. It is important to remember that before you start pouring cement mortar, you will need to check the accuracy of the location of the blocks in the ditch.

If necessary, fixed formwork for the base of expanded polystyrene is reinforced with additional elements. It is very important to achieve the correct base geometry. This technology has many advantages. When using non-removable blocks made of polystyrene foam, the cost of organizing the foundation is reduced by at least a third.

Formwork for a monolithic foundation : stages of self-installation

After organizing the foundation of the future structure, you can proceed with the installation of formwork. This operation is conditionally divided into three stages: installing blocks, knitting reinforcement and pouring the mortar. Each stage is carried out in accordance with building codes. During operation, safety precautions must be observed. Let’s consider each stage in more detail.

Installation of blocks. First, the first row of molds is mounted, which will be used for pouring concrete. It should be noted that installation is carried out only on the waterproofed surface of the base. The formwork for the base of polystyrene foam must be tightly fixed due to the reinforcement rods. These elements are the link between the base and the formwork itself.

First, the first row of formwork is mounted, which will be used for pouring concrete
First, the first row of formwork is mounted, which will be used for pouring concrete

Experts advise checking the accuracy of the work performed, since a deviation from the original design dimensions is possible. The presence of branch bends for partitions is also a very important point to which attention must be paid. After organizing the first row, you can start laying the second. The technology of mounting blocks involves a chess system in which each subsequent row is shifted relative to the previous one. As a result, the joint of the elements of the first row should fall in the middle of the block of the second strip.

Knitting reinforcement. Mounting a metal structure is one of the most important aspects of organizing any type of construction cake. The fittings are used to strengthen the foundations, walls, as well as monolithic ceilings. The formwork for the foundation, consisting of blocks that are stacked in rows, should be girded around the perimeter with rods located in a horizontal plane.

In order to simplify the installation of fittings, special grooves are provided in each block, which are located in jumpers (internal). Horizontal rods are mounted in such a way that each subsequent element goes to the previous one (overlap). Further, the rods are connected to each other, as well as to vertical elements using a special wire.

Note! Reinforcement allows not only to increase the structural strength, but also to reduce the cement pressure on the mold.

Pouring solution. Before starting to fill in the fixed formwork with your own hands, it is recommended to take care of laying the communications inside the forming structure. The cement mortar used to form the formwork must not contain extraneous additives and impurities (e.g. crushed stone). The operation itself is quite simple. Pouring is carried out step by step, and the height of the concrete layer should not exceed 1 m. This indicator corresponds to the size of 3-4 fixed blocks of the structure.

The price of fixed formwork for the foundation is lower than the cost of standard analogues, which involve the use of plywood and boards. It is important to remember that the poured solution requires leveling. For these purposes, a special tool is used – a vibrator. In the absence of the necessary electrical equipment, you can use a conventional bayonet shovel.

Fixed formwork for walls : casting technology

The independent use of such a method of casting walls requires an understanding of the process. Most often, this type of construction is used by non-professionals in the case of the construction of private one-story houses, as well as garage structures. The construction of polystyrene formwork foam can be carried out alone. However, few people will install the walls much faster.

The advantage of using forms of expanded polystyrene is that they have a small mass. Thus, physical activity in this case is reduced to a minimum. Before starting construction, it is necessary to study the step-by-step algorithm of actions and nuances that allow you to answer the question of how to properly formwork.

Walls made using this method are recommended to be installed on a strip foundation. This base is best suited for construction using non-removable foam forms. It is important to remember that the use of cement mortar for pouring walls often imposes a certain limit on the number of rows of blocks. Experts advise to have 4 rows of shapes, and they should be reliably connected to the base of the building by means of reinforcement.

installing fixed blocks
When installing fixed blocks of expanded polystyrene, special attention must be paid to their docking

Useful information! It is not recommended to immediately pour all the concrete. First, a partial pour should be made and wait some time necessary for the solution to shrink. As a rule, such a procedure takes no more than 3-4 hours. Next is the addition of cement mortar.

When erecting monolithic structures for casting walls, special forms are often used – shields. They are connected using special coupling bolts and form a gap in which concrete is poured. Such products may have various dimensions. For example, their maximum height is 3.3 m, and the width indicator ranges from 0.25 to 2.4 m. After the solution solidifies, this structure is dismantled. The size of the formwork shield is selected depending on the individual characteristics of the structure being constructed.

It is worth noting that another feature of the fixed formwork used to fill the walls is its instability. This is due to the fact that concrete poured into molds has a large mass. Thus, even blocks laid in 4 rows and equipped with fittings need a daily wait. This time is enough for the solution to settle and condense.

advantage of using forms of expanded polystyrene
The advantage of using forms of expanded polystyrene is that they have a small mass

When installing non-removable blocks made of polystyrene foam, special attention must be paid to their docking. Individual structural elements must be combined with extreme care so that the surface of the first rows is as even as possible. Otherwise, when adding the following rows, the wall may collapse due to their skew.

An alternative to polystyrene foam is plastic. Plastic formwork for monolithic construction is used when it is required to ensure good strength and rigidity of the structure. The advantage of such products is that they are highly durable.

Finishing walls after pouring them: recommendations

Facing work allows not only to give the wall cast in the formwork a complete look, but also to strengthen its protective characteristics. Finishing is done on almost all types of structures. After filling the wall, as a rule, there is no need for its alignment. This is due to the design of the forms. Thus, the need for applying a thick layer of plaster disappears.

Saving on the finishing of walls and other surfaces is not worth it, since the total cost of work is already reduced through the use of expanded polystyrene. The price of this material is much lower than the cost of traditional formwork options.

Cladding works
Cladding works can enhance the protective characteristics of formwork

Most often, a special mesh is sufficient for wall decoration, which can be made of fiberglass or metal. Such a mesh is joined to the concrete surface with the help of an adhesive composition, after which it is sealed with plaster or putty.

It is in this way that not only standard rectangular walls are processed, but also round columns. Formwork for such structures is most often made of plastic. There are cardboard options for forms.

Note! In addition to standard methods of finishing the outer surface of concrete, there are other, no less popular options. For example, very often tiles and artificial stone are used as cladding.

For interior wall decoration, as a rule, plasterboard material is used. GKL installation is carried out in two ways – using profile elements or glue. This method of facing is very popular not only because of its simplicity and effectiveness, but also because this material provides good sound insulation.

Finishing walls
Often, tiles and artificial stone are used as cladding

Racks for the organization of a fixed form of ceilings

The traditional option of organizing ceilings in monolithic or any other buildings involves the use of special telescopic (sliding) racks. These products are used to fix the temporary flooring, which is made of waterproof plywood for formwork. This method is not convenient, since it requires a lot of time and rather large physical exertion.

The stand, performing the supporting role, consists of several structural elements. The lower part of the telescopic product is equipped with a tripod, which ensures the stability of the pipe. In turn, in the upper part there is a special nozzle, which is necessary to capture and hold the building beam – the crossbar. All racks for formwork floors are divided into two categories depending on the location of the thread. Some of them are equipped with open threads, while others are closed.

The pipe, which has a smaller cross section, is characterized by the presence of special holes along its entire length. The pitch of the holes can be different – from 11 to 17.5 cm. The outer pipe is equipped with a support nut. As a result, when it becomes necessary to fix the rack at a certain level, a special earring is inserted through holes in the pipes. This element has a support (nut), therefore it is held in position.

organization of ceilings
The organization of ceilings in monolithic and not only buildings, involves the use of special telescopic sliding racks

Telescopic formwork racks can vary in length. This indicator ranges from 1.7 to 4.5 m. They withstand quite large loads (up to 4 tons). It is worth noting that such supporting products are made of metal, so they are coated with special anti-corrosion compounds, since steel can rust.

Fixed formwork for floors : features and characteristics

Unlike the standard method, which assumes the presence of support columns, polystyrene formwork for floors has a completely different installation technology. As a basis for such a system, special matrices are used, which are made from dense and durable polystyrene foam.

Such matrices should be laid on load-bearing walls. The advantage of this method is that these elements have a small mass, therefore, serious physical effort is not required to install them.

Note! Before starting work, it is necessary to calculate the formwork of the floor.

special matrices
As a basis for formwork, special matrices are often used, which are made from dense and durable polystyrene foam

Docking matrices among themselves is quite simple. Each product is equipped with a tongue-and-groove system for connection. Thus, any person who does not have work experience in this area will be able to perform a similar installation. Thanks to the tongue-and-groove system, it becomes possible to quickly organize a continuous flooring.

Such a formwork for monolithic overlap is able to withstand a layer of concrete up to 15 cm thick. As a rule, this value is quite enough to organize a reliable structure. Before embarking on concrete pouring, it is necessary to position the reinforcement between the joint zones of the floor elements. The metal frame must be assembled into a continuous beam, occupying the entire width of the gap.

Then on top of the matrices you need to place the reinforcing mesh. It is made of rods, the diameter of which is from 10 to 15 mm. Reinforcement is knitted in the traditional way – using a special wire.

The final stage of creating a bulk formwork of the floors involves pouring concrete, after which it is necessary to wait for it to solidify. Thus, the organization of the floors using polystyrene matrices. The result of this process is a robust design that can withstand significant loads.

Fixed formwork for floors
Any design errors or the displacement of the blocks during installation can lead to collapse of the structure

After the cement mortar hardens, the polystyrene formwork foam is not dismantled. It remains in the slab and from this moment begins to perform the heat-insulating function. This method of organizing the design is more technologically advanced when compared with the traditional method, taking into account the use of removable beams for formwork floors.

It is important to remember that the independent use of such a technology requires an understanding of its nuances. The main thing is that even before you start working, you need to know that laying overlapping elements requires accuracyAny design errors or the displacement of the blocks during their installation can lead to collapse of the structure.

Fixed formwork: prices in the modern market

The cost of blocks is an important point to pay attention to. Two key factors affect the price of the building blocks from which the fixed formwork is made:

  • polystyrene foam density;
  • dimensions of parts.
Fixed forms are a good economical alternative
Fixed forms are a good economical alternative to standard designs that are assembled from wood and plywood

The price of fixed polystyrene formwork foam foundation must be taken into account in the construction estimate. When choosing individual elements of the forming structure, it is recommended to pay attention to their density. This indicator affects the structural stability to pressure. The higher the density of the parts, the correspondingly higher loads they can withstand.

Note! Experts advise to purchase blocks, the density of which varies from 25 to 35 kg / m³.

The average cost of a block made of polystyrene foam is approximately 2.24$. It is worth considering that at such a price products with dimensions of 1500x250x250 mm have a density of 30 kg / m³. Designs with a length of 1.5 m have an adjustment function due to the installation of jumpers of different sizes (15-25 cm). Products whose length is 1 m are cheaper – from 1.82$. for 1 pc.

If you plan to use standard construction technology, then it is recommended to study the cost of various materials. The price of telescopic racks depends on the features of their design and the manufacturer’s company. Currently, these supporting elements can be purchased for 7-70$. It is not recommended to buy the cheapest materials and tools, as they most often have low technical characteristics.

prices in the modern market
Two factors influence the price of the blocks from which the fixed formwork is performed: the density of expanded polystyrene and the dimensions of the parts

Supporting elements are used to hold the wooden structure, which is made of laminated plywood for formwork. The price of 1 sheet of such material varies from 8,50 to 42$.

Fixed forms are a good alternative to standard designs that are assembled from wood and plywood. Such formwork allows not only pouring concrete, but also serves as a reliable heat-insulating material. It is actively used in private construction, but requires the study of installation instructions and compliance with safety rules.


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